a. Field of Invention
The invention relates to a method for the numerical control of the path of a polygonal punching tool of a punch press wherein the tool can be rotated in the punching direction about an axis of rotation in such a manner that the cutting edge of the tool can be guided tangentially along the contour of a workpiece.
b. Description of the Prior Art
It is customary to employ so-called nibble machines to work sheet metal parts with a given contour from metal sheets. If the nibbling tool is round, a relatively large number of punching strokes per unit of distance must be made when linear sections of the contour are to be punched, in order to avoid roughness. Therefore, the speed with which a workpiece can be generated may be greatly limited. For this reason, polygonal punching tools are used in modern punching machines which punch out with every punching operation a large section of the desired contour as compared to a nibbling process with round tools. (All tools deviating very much from the circular form can be designated as polygonal.) The polygonal tool is made rotatable, so that contours can be processed in any desired direction as an inside as well as an outside contour. The setting of the paths for the punching tool in the numerical control of a punching machine is relatively costly since the path must first be divided into a multiplicity of subpaths which are set into the control individually.